Method of effecting cyclization



United States Patent 3,138,612 METHGD 0F EFFECTING CYCLIZATION Valentine M. Kasmer, Buffalo, N.Y., assignor to Allied Chemical Corporation, New York, N .Y., a corporation of New York No Drawing. Filed Sept. 1, 1960, Ser. No. 53,367 10 Claims. (Cl. 260316) This invention relates to an improved method of effecting the cyclization of organic polycyclic compounds with caustic alkalis. It relates more particularly to an improved method for carrying out the production of polycyclic organic compounds, and especially organic vat dye stuffs and pigments, from polycyclic organic intermediate compounds having a lesser number of ring members, and especially from anthrimide intermediate compounds, by heating said intermediate compounds with caustic alkalis.

A number of valuable vat dyestuffs, pigments and other polycyclic organic compounds are currently produced by methods which involve a fusion of an organic intermediate polycyclic compound with caustic alkali. Although it is known to conduct such fusions with molten caustic alkali at high temperatures, it is the more common practice to use alcoholic caustic alkali in view of the more fluid melts obtained at less elevated temperatures. For reasons of convenience and ease of handling, the more expensive caustic potash (potassium hydroxide) has been preferred over caustic soda (sodium hydroxide). The requirement of obtaining a fluid melt which could be efficiently agitated gave rise to the necessity of using large amounts of the costly caustic alkali (of the order of 4 to 5 and often more parts per part by weight of intermediate compound). These factors resulted in increased cost of materials and severely restricted the effective capacity of a given piece of apparatus; and the necessary large bulk of materials required resulted in relatively large labor costs for their transporting and handling. Further, inasmuch as the major bulk of the materials used did not appear in the final product, their elimination after they had served their function as reaction medium was a tedious and labor consuming task.

A prime object of the present invention is to provide an improved method for effecting the cyclization of organic intermediate polycyclic compounds with caustic alkali whereby these objections are overcome.

A further object of the present invention is to provide an improved process for carrying out the production of polycyclic organic compounds by cyclization of organic intermediate polycyclic compounds with caustic alkali in which greatly reduced amounts of caustic alkali are employed.

A further object of the present invention is to provide an improved process for cyclizing anthrimide intermediate compounds with caustic alkalis which results in significant savings in the consumption of materials and in labor costs.

Other objects of the invention will in part be obvious and will in part appear hereinafter.

According to the present invention, the production of polycyclic organic compounds by cyclization and dehydrogenation of organic intermediate polycyclic compounds having a lesser number of ring members, with the aid of caustic alkali, is effected by heating the organic intermediate polycyclic compound in admixture with an amount of caustic alkali suflicient to provide an alkaline reaction mixture at a temperature of about 150 C. to about 350 C. while subjecting the mixture to attrition and mechanical grinding, for example, in a rotating tumbling mill reactor.

I have discovered that the cyclization with the aid of caustic alkali can be effected in said manner, without requiring the use of substantially greater amounts of "Ice caustic alkali than about twice the Weight of the organic polycyclic compound to be cyclized, and without requiring the inclusion in the reaction mixture of a liquid or flux (such as, an alcohol, alcoholate, phenol or phenolate) in suflicient amount to provide a liquid reaction mixture, both of which were heretofore considered essential, and yet the yield and quality of cyclized product are not adversely affected.

I have further discovered that the reaction proceeds rapidly and satisfactorily, without impairment of yield or quality of product, even though the reaction mixture is in the substantially solid state.

This result is surprising, since heretofore it was considered essential to employ large amounts of molten caustic alkali, at high temperatures or with the addition of a flux, in order to provide the liquid medium believed to be necessary for carrying out the cyclization reaction.

The invention is not limited to the use of any specific form of apparatus. The apparatus employed in carrying out the process of the present invention may be any type of rotary reactor adapted to heat the polycyclic organic intermediate compound, caustic alkali, and other reaction components (if any) to the desired reaction temperature while subjecting the reaction mass to attrition and mechanical grinding. Any rotatable ball mill or rod mill equipped with suitable means for heating, temperature control, charging and discharging of reactants and products, as well as means for providing access of the interior of the reactor to the atmosphere or for removing vapors, can be employed. A number of such reactors are well known. Thus, US. Patents 1,862,557, 1,862,575 and 2,153,300 disclose suitable reactors.

Various materials of construction can be employed in fabricating the reactors for use in accordance with the present invention. Iron and steel are sufficiently resistant to the action of caustic alkalis at high temperatures to be suitable for the purposes, and in View of their relatively low cost they are preferably employed.

Various tumbling elements adapted to tumble and slide during the rotation of the reactor, such as metallic balls, rods, slugs, and other suitable materials in various solid forms, can be employed alone or together as means for effecting attrition and grinding of the reaction components and products in the rotary reactor. By their constant and unrestricted movement while the reactor is being rotated, they effectively agitate and grind the substantially dry, solid reaction mixture during the reaction period. Iron and steel balls and rails are convenient grinding members, but other materials can be used.

In carrying out the cyclization in accordance with the improved process of this invention, the polycyclic organic intermediate compound and about one-half to twice its weight of caustic alkali are added to the rotary tumbling mill type reactor, together with other reactants, as required, such as, reducing agents, oxidizing agents, catalysts, etc. The reactants may be added in the dry state and blended by milling in the reactor or may be premixed by mixing in any suitable apparatus; or they may be charged to the reactor as aqueous pastes or solutions and the water evaporated therefrom in the first stage of the heating period. Thereafter, the rotation of the apparatus is begun or continued, and the mixture is heated to reaction temperature, usually above about C.

The reaction mass is maintained at the predetermined temperature for a suitable period to complete the cyclization while the mass is constantly being ground and subjected to tumbling and attrition by the unrestricted elements within the rotating reactor. Thereafter the mass is cooled and removed from the reactor in a suitable manner (as by rinsing with water, by solution in a suitable solvent, or by other means), and the resulting cyclized polynuclear product is processed in the usual manner to produce the desired finished product.

It is preferable to continue the rotation of the reactor after the cyclization step has been completed and while the reacted mass is being cooled. Continuation of the grinding and attrition results in a cooled product in finely divided form, which simplifies the removal of the product. By suitable design of the reactor, facilities can be incorporated which will permit the entire batch to be removed from the reactor at the completion of the heating cycle, or which will permit the cooled subdivided product to be removed from the reactor in the dry state or otherwise.

The yield and quality of the resultant cyclized products are generally equal to or superior to those obtained by the known caustic fusion procedures, wherein the ring closure step is effected in the presence of very much larger proportions of caustic alkali, in the presence or absence of one or more fluxing agents, such as lower aliphatic alcohols, alkali metal salts of fatty acids or phenols, etc.

Caustic potash (potassium hydroxide) is the preferred alkaline cyclizing agent, but other caustic alkalis can be used, such as caustic soda (sodium hydroxide), and mixtures of caustic soda and caustic potash. The amount of caustic alkali employed is not critical, but sufficient should be used to provide an alkaline reaction mixture and such can be obtained when about one-half to about 2 parts are employed per part by weight of organic intermediate polycyclic compound used. In most instances about equal parts of caustic alkali and of intermediate polycyclic compound is satisfactory and hence is to be preferred. It is a feature of the present invention that amounts of caustic alkali substantially greater than 2 parts are not required to obtain high yields and quality of cyclized products.

The reaction temperature can be varied over a considerable range. The minimum temperature is that at which the intermediate compound is activated sufficiently by the caustic alkali to undergo cyclization at an acceptable rate, generally about 150 C. The maximum temperature is that at which the intermediate compound begins to undergo appreciable decomposition. This, of course, will vary depending upon the specific intermediate compound. Although temperatures of about 350 C. have been used, in general it is rarely necessary to carry out the process at temperatures above 250 C.

The time required will vary with the specific compound employed, as well as with the temperature used. Generally, when operating at 160 C. to 240 C., the time required to substantially complete the reaction will range from 1 to 6 hours.

The process of the present invention is applicable to the cyclization of various polycyclic organic intermediate compounds which are capable of being converted to more highly cyclized compounds with formation of a new carbocyclic or heterocyclic nucleus and with elimination of hydrogen (dehydrogenation) by fusion with a caustic alkali, many of which are known. Thus it is applicable to the manufacture of vat dyes, pigments and intermediates therefor from various naphthalene, anthraquinone, benzanthrone, and related polycyclic organic intermediate compounds customarily employed for the manufacture of organic polycyclic compounds containing a greater number of rings. It is especially useful in connection with the manufacture of anthraquinone vat dyestufis and pigments containing nitrogen as a heterocyclic ring member in combination with one or more anthraquinone and/ or benzanthrone nuclei, more particularly, by cyclization and dehydrogenation of an anthrimide intermediate compound, and especially by cyclization and dehydrogenation of an anthraquinonylaminobenzanthrone.

The invention will be illustrated by the following specific examples, but it is to be understood that it is not limited to the details thereof and that changes may be made without departing from the scope of the invention. The temperatures are in degrees centigrade and the parts and percentages are by weight, unless designated as parts by volume. Where parts are by volume, the amount signifies the volume occupied by the same number of parts by weight of water at 4 C.

EXAMPLE 1 C.I. Vat Black 25 (CI. No. 69525) Seven hundred and sixty parts of solid potassium hy droxide (caustic potash flakes) were charged to a rotary ball mill reactor containing crude 3,9-bis(l-anthraquinonylamino)-benzanthrone in the form of a reaction mixture resulting from the interaction of 375 parts of 3,9-dibromobenzanthrone, 463 parts of l-aminoanthraquinone, 229 parts of sodium carbonate (soda ash) and 281 parts of an intimate mixture of 2 parts sodium carbonate and 1 part of copper (II) sulfate pentahydrate at 270 to 280 for about 16 hours. The ball mill reactor employed was similar to that shown in US. Patents 1,862,557 and 1,862,575 and was formed of an externally heated, horizontal, cylindrical steel tank, about 8 feet long and 6 feet in diameter, pivoted on hollow trunnions and provided with openings for charging and testing. The tank was charged, to a depth of about 2 feet (measured on the diameter) with iron balls about 4 inches in diameter and several pieces of steel railroad rails about 5 to 6 feet long, as grinding and mixing elements. Suitable condensing means were connected to one of the hollow trunnions, and the apparatus was further provided with the usual conventional equipment, as well as conventional means for rotating the tank.

The ball mill reactor was charged with a volume of the reaction mixture in said proportions sufiicient to fill it (together with the iron balls and rails) to a depth of about 2V2 feet.

The reactor was closed and rotated, first without heating for about 16 hours, to permit the solid mixture to be ground and mixed thoroughly, and then while being heated to 185 to 200 (internal temperature) in about 4 hours, at which temperature it was held for about 1 hour. The reactor was permitted to rotate while cooling to below 100, at which temperature the reactor was opened and 1500 parts of water were added. The reactor was closed and rotated for about an hour and a half, then the aqueous slurry of reaction product was removed and the reactor was flushed out with water several times, the washings being added to the aqueous slurry. The resulting product slurry was aerated While being heated to to to complete the oxidation of the cyclized compound to Cl. Vat Black 25, the mass was filtered, and the filter cake was washed with water until alkali free. The washed cake was dried.

When the resulting product (C.I. Vat Black 25) was converted in the usual manner to a vat dyestuif paste and employed as a vat dyestuff for cotton in the conventional manner, it gave dyeings which were equal in all respects to the corresponding C.I. Vat Black 25 which had been prepared by a process conventionally employed to manu facture the dyestuff commercially and in which about 2400 parts of potassium hydroxide and 720 parts of ethanol were used to effect cyclization of the foregoing amount of crude 3,9-bis(l-anthraquinonylamino)benzanthrone.

EXAMPLE 2 C1. Vat Green 3 (CJ. No. 69500) A mixture of 68 parts of 3-(l-anthraquinonylamino)- benzanthrone (which had been prepared by the condensation of 3-bromo-benzanthrone with 1-amino-anthraquinone), 84 parts of potassium hydroxide flakes (caustic potash), 17 parts of sodium carbonate (soda ash) and parts of water was charged to a ball mill reactor similar to that used in Example 1, but of smaller size, and the mixture was rotated therein while the reactor was heated to 150 to evaporate the water, the vapor being removed through the hollow trunnion of the reactor. Thereafter the mixture was heated to and maintained at 160 to 165 for about 3 hours. Rotation of the reactor was continued While it was permitted to cool to about 25, at which temperature 750 parts of water were added. The reactor was rotated for about 1 hour, and then the fluid mass was discharged and the reactor was flushed out with about 4000 parts of water, the washings being added to the product. The resulting aqueous slurry was heated and aerated at just below its boiling point to complete oxidation of the cyclized product. The oxidized product was filtered, and the filter cake was washed alkali free. The washed cake was reslurried in 1000 parts of dilute hydrochloric acid muriatic acid), boiled for 1 hour, filtered and washed acid free with water.

When the resulting product (Cl. Vat Green 3) was converted in the usual manner to a vat dyestuif paste and employed as a vat dyestuff for cotton in the conventional manner, it gave dyeings which were equal in all respects to the corresponding C.I. Vat Green 3 which had been prepared by a process conventionally employed to manufacture the dyestutf commercially and in which about 303 parts of potassium hydroxide and 144 parts of methanol were used to provide the reaction medium for the foregoing amount of 3 (1 -anthraquinony1amino)-benzanthrone.

EXAMPLE 3 CJ. Vat Black 13 A ball mill of the type employed in Example 2 was charged with 49 parts of amino-3,3'-dibenzanthronyl, 28 parts of solid potassium hydroxide, 12 parts of sodium sulfide, 21 parts of sodium carbonate (soda ash), and 100 parts of water. The mill was rotated and heated to 160 to 170 and maintained thereat for about six hours, during the first two hours of which the water was evaporated and the mixture became dehydrated. Ring closure then proceeded for about the other four hours. The mill was permitted to cool to about 25, then 750 parts of water were added, and the resulting aqueous mixture was agitated in the mill for about an hour and a half and then discharged. The mill was flushed with sufficient water to form about 3000 parts (by volume) of slurry when added to the aqueous mixture. The slurry was heated to just below its boiling point, aerated to complete oxidation of the cyclized product, and filtered. The filter cake was washed alkali free.

When the resulting product ((31. Vat Black 13) was converted in the usual manner to a vat dyestuif paste and employed as a vat dyestufi for cotton in the conventional manner, it gave dyeings which were equal in all respects to a corresponding C.I. Vat Black 13 which had been prepared by a process conventionally employed to manufacture the dyestuff commercially and in which 49 parts of the amino-3,3'-dibenzanthronyl were fused with about 143 parts of potassium hydroxide and 225 parts of isopropyl alcohol.

EXAMPLE 4 CJ. Vat Blue 4 (Indanthr0ne--C.I. No. 69800) A mixture of 75 parts of 2-aminoanthraquinone, 100 parts of solid potassium hydroxide and 5 parts of sodium nitrate was ground and mixed in a ball mill reactor of the type employed in Example 2, as it was heated to about 160 in an hour and a half. The reaction was continued at 160 to 170 for 1 hour and then, as rotation was continued, the reactor was permitted to cool to below 100. The reaction mass was diluted with 8000 parts of water and after being thoroughly mixed in the reactor the aqueous slurry was removed. The mass, after addition of 50 parts of sodium hydrosulfite, was heated to and maintained at 97 for a half hour and then filtered. The filter cake was washed with a dilute caustic alkaline solution of hydrosulfite. The washed cake was reslurried in about 1000 parts of water to which 25 parts of sodium Intermediate: Dyestufi 1,1 bis benzamido 5,5-

dianthrimide C.I. Vat Orange 15 (Cl. No. 69025).

2,2 dimethyl 1,1 dianthraquinonyl C.I. Vat Orange 9 (Cl. No. 59700). 2,2 bis(1 anthraquinonylamino)-dibenzanthrone 3,3-dibenzanthronyl sulfide C.I. Vat Black 18. CI. Vat Violet 10 (Isoviolanthrone- 0.1. No. 6000). 0.1. Vat Blue 2 0 (Violanthrone- OJ. No. 59800). 3,4,9,10-Perylenetetracarboxylic diimide (Colour Index, Second Edition, vol. 3, p. 3750).

Benzanthrone Naphthalimide It is also possible to employ the rotary tumbling mill reactor for other synthesis reaction in conjunction with the cyclization, thereby effecting additional economies. For example, one or more of the intermediates employed in the cyclization reaction can be prepared, as a preliminary operation, in the rotary reactor prior to the cycliza tion reaction; or formation of the desired intermediate can be carried out in the cyclization reaction medium; or subsequent treatment of the cyclization reaction product can be carried out in the same rotary reactor.

Thus, in connection with the manufacture of Cl. Vat Black 25, disclosed in above Example 1, preparation of the crude 3,9-bis(anthraquinonylamino)-benzanthrone can be carried out in the same reactor, as a preliminary operation, by charging the ball mill reactor employed in Example 1 with the 3,9-dibromo-benzanthrone, l-aminoanthraquinone, sodium carbonate, and sodium carbonatecopper sulfate mixture through an opening in the wall of the reactor, closing the opening and heating and rotating the reactor until formation of the 3,9-bis(anthraquinonylamino)-benzanthrone is completed, then cooling the resulting crude reaction mixture to approximately 50, while continuing the rotating of the reactor, opening the reactor, charging the solid potassium hydroxide, closing the reactor, and then proceeding with the process of above Example 1.

In the manufacture of C. I. Vat Black 13, by the process of Example 3, the corresponding amount of nitro-3 ,3 dibenzanthronyl can be substituted for the amino-3,3'- dibenzanthronyl employed in Example 3 and the identical product can be obtained, by employing a sufficiently greater proportion of sodium sulfide in the reaction mixture to effect reduction of the nitro group to the amino group in conjunction with the cyclization reaction.

As is evident from the above examples, the alkaline reaction mixtures can contain additional compatible solid salts. Thus in the cyclization of anthrirnide bodies, alkali metal carbonates and preferably sodium carbonate can be advantageously used. In the cyclization of simple aminoanthraquinones, alkali metal nitrates, and preferably sodium nitrate can be present. The amounts of these additional compatible solid salts used are not critical and generally will vary between and 50% by weight of the organic polycyclic compound. Preferably this amount is about 20% by weight of said polycyclic compound. Accordingly, it is intended that the claims appended hereto shall include the use of such compatible solid salts together with the caustic alkali.

I claim:

1. The improvement in the method of producing a polycyclic organic compound selected from the group consisting of vat dyestuffs, pigments and intermediates therefor wherein an organic intermediate polycyclic compound having a lesser number of rings and selected from the group consisting of anthrimides, amino-dibenzanthronyls, Z-amino-anthraquinone, 2,2-dimethyl-1,l-dianthraquinonyl, dibenzanthronyl-sulfides, benzanthrones and naphthalimides is cyclized and dehydrogenated with the aid of caustic alkali, which comprises heating the organic intermediate polycyclic compound in solid form in admixture with a caustic alkali in solid form in an amount sufficient to provide an alkaline reaction mixture, at a temperature of about 150 C. to about 350 C., while subjecting the mixture to attrition and mechanical grinding.

2. The improvement in the method defined in claim 1, which comprises heating said mixture at a temperature of 150 C. to 250 C. while contained in a rotating tumbling mill reactor.

3. The improvement in the method of producing a polycyclic organic compound selected from the group consisting of vat dyestuffs, pigments and intermediates therefor wherein an organic intermediate polycyclic compound having a lesser number of rings and selected from the group consisting of anthrimides, amino-dibenzanthronyls, 2 amino-anthraquinone, 2,2'-dimethyl 1,1-dianthraquinonyl, dibenzanthronyl-sulfides, benzanthrones and naphthalimides is cyclized and dehydrogeuated with the aid of caustic alkali, which comprises heating the organic intermediate polycyclic compound in admixture with one-half to twice its weight of caustic alkali at a temperature of about 150 C. to about 250 C. while subjecting the mixture in substantially solid form to attrition and mechanical grinding.

4. The improvement in the method defined in claim 3 which comprises carrying out the heating in a rotating ball mill reactor.

5. A method of producing an anthraquinone vat dyestulf, by cyclization and dehydrogenation of an anthrirnide with the aid of caustic alkali, which comprises heating the anthrirnide in solid form in admixture with about onehalf to about twice its weight of solid caustic alkali at a mi temperature of about 150 C. to about 250 C. while subjecting the mixture to attrition and mechanical grinding.

6. A method of producing an anthraquinone vat dyestufl, by cyclization and dehydrogenation of an anthrirnide With the aid of caustic alkali, which comprises heating the anthrirnide in solid form in admixture with about one-half to about twice its weight of solid potassium hydroxide at a temperature of about 150 C. to about 200 C. while subjecting the mixture to attrition and mechanical grinding in a rotating tumbling mill reactor.

7. A method of producing an anthraquinone vat dyestuff, by cyclization and dehydrogenation of an anthraquinonylamino-benzanthrone with the aid of caustic alkali, which comprises heating the anthraquinonylaminobenzanthrone in admixture with about one-half to about twice its weight of caustic alkali at a temperature of about 150 C. to about 250 C. while subjecting the mixture in substantially solid form to attrition and mechanical grinding.

8. A method of producing an anthraquinone vat dyestuff, by cyclization and dehydrogenation of an anthraquinonylamino-benzanthrone with the aid of caustic alkali, which comprises heating the anthraquinonylamino-benzanthrone in solid form with about one-half to about twice its weight of solid potassium hydroxide and from 5 to of its Weight of an alkali metal carbonate at a temperature of about C. to about 200 C. while subjecting the mixture to attrition and mechanical grinding in a rotating tumbling mill reactor.

9. The method of claim 8 wherein the alkali metal carbonate used is sodium carbonate.

10. A method of producing an anthraquinone vat dyestuff, by cyclization and dehydrogenation of an anthraquinonylamino-benzanthrone with the aid of caustic alkali, which comprises heating the anthraquinonylaminobenzanthrone in admixture with about an equal amount of its weight of potassium hydroxide and about 20% of its weight of sodium carbonate at a temperature of about 150 C. to about 200 C. while subjecting the mixture in substantially solid form to attrition and mechanical grinding in a rotating tumbling mill reactor.

References Cited in the file of this patent UNITED STATES PATENTS 2,766,244 Brouillard Oct. 9, 1956 2,930,792 Fleysher Mar. 29, 1960 FOREIGN PATENTS 230,407 Germany a- Jan. 23, 1911 

1. THE IMPROVEMENT IN THE METHOD OF PRODUCING A POLYCYCLIC ORGANIC COMPOUND SELECTED FROM THE GROUP CONSISTING OF VAT DYESTUFFS, PIGMENTS AND INTERMEDIATES THEREFOR WHEREIN AN ORGAIC INTERMEDIATE POLYCYCLIC COMPOUND HAVING A LESSER NUMBER OF RINGS AND SELECTED FROM THE GROUP CONSISTING OF ANTHRIMIDES, AMINO-DIBENZANTHRONYLS, 2-AMINO-ANTHRAQUINONE, 2.2''-DIMETHYL-1,1''-DIANTHRAQUINONYL, DIBENZANTHRONYL-SULFIDES, BENZATHRONES AND NAPHTALIMIDES IS CYCLIZED AND DEHYDROGENATED WITH THE AID OF CAUSTIC ALKALI, WHICH COMPRISES HEATING THE ORGANIC INTERMEDIATE POLYCYCLIC COMPOUND IN SOLID FORM IN ADMIXTURE WITH A CAUSTIC ALKALI IN SOLID FORM IN AN AMOUNT SUFFICIENT TO PROVIDE AN ALKALINE REACTION MIXTURE, AT A TEMPERATURE OF ABOUT 150*C. TO ABOUT 350*C., WHILE SUBJECTING THE MIXTURE TO ATTRITION AND MECHANICAL GRINDING.
 5. A METHOD OF PRODUCING AN ANTHRAQUINONE VAT DYESTUFF, BY CYCLIZATION AND DEHYDROGENATION OF AN ANTHRIMIDE WITH THE AID OF CAUSTIC ALKALI, WHICH COMPRISES HEATING THE ANTHRIMIDE IN SOLID FORM IN ADMIXTURE WITH ABOUT ONEHALF TO ABOUT TWICE ITS WEIGHT OF SOLIC CAUSTIC ALKALI AT A TEMPERATURE OF ABOUT 150*C. TO ABOUT 250*C. WHILE SUBJECTING THE MIXTURE TO ATTRITION AND MECHANICAL GRINDING. 